Hydrogen peroxide found in space

Molecules of hydrogen peroxide have been found for the first time in interstellar space. The discovery gives clues about the chemical link between two molecules critical for life — water and oxygen. On Earth, hydrogen peroxide plays a key role in the chemistry of water and ozone in our planet’s atmosphere, and is familiar for its use as a disinfectant or to bleach hair blonde. Now, it has been detected in space by astronomers using the European Southern Observatory-operated Atacama Pathfinder Experiment (APEX) telescope in Chile.

An international team of astronomers made the discovery with APEX, situated on the 16,400-foot-high (5,000 meters) Chajnantor plateau in the Chilean Andes. They observed a region in our galaxy close to the star Rho Ophiuchi, about 400 light-years away. The region contains cold (around -420° Fahrenheit [-250° Celsius]), dense clouds of cosmic gas and dust in which new stars are being born. The clouds are mostly made of hydrogen, but contain traces of other chemicals, and are prime targets for astronomers hunting for molecules in space. Telescopes such as APEX, which make observations of light at millimeter- and submillimeter-wavelengths, are ideal for detecting the signals from these molecules.

Now, the team has found the characteristic signature of light emitted by hydrogen peroxide, coming from part of the Rho Ophiuchi clouds.

“We were really excited to discover the signatures of hydrogen peroxide with APEX. We knew from laboratory experiments which wavelengths to look for, but the amount of hydrogen peroxide in the cloud is just one molecule for every 10 billion hydrogen molecules, so the detection required very careful observations,” said Per Bergman from Onsala Space Observatory in Sweden.

Hydrogen peroxide (H2O2) is a key molecule for both astronomers and chemists. Its formation is closely linked to two other familiar molecules, oxygen and water, which are critical for life. Because much of the water on our planet is thought to have originally formed in space, scientists are keen to understand how it is created.

Hydrogen peroxide is thought to form in space on the surfaces of cosmic dust grains — fine particles similar to sand and soot — when hydrogen (H) is added to oxygen molecules (O2). A further reaction of hydrogen peroxide with more hydrogen is one way to produce water (H2O). This new detection of hydrogen peroxide will therefore help astronomers better understand the formation of water in the universe.

“We don’t understand yet how some of the most important molecules here on Earth are made in space,” said Berengere Parise from the Max Planck Institute for Radio Astronomy in Germany. “But our discovery of hydrogen peroxide with APEX seems to be showing us that cosmic dust is the missing ingredient in the process.”

To work out just how the origins of these important molecules are intertwined will need more observations of Rho Ophiuchi and other star-forming clouds with future telescopes such as the Atacama Large Millimeter/submillimeter Array — and help from chemists in laboratories.

The Rho Ophiuchi star formation region, where hydrogen peroxide has been detected in space. ESO/S. Guisard

Molecules of hydrogen peroxide have been found for the first time in interstellar space. The discovery gives clues about the chemical link between two molecules critical for life — water and oxygen. On Earth, hydrogen peroxide plays a key role in the chemistry of water and ozone in our planet’s atmosphere, and is familiar for its use as a disinfectant or to bleach hair blonde. Now, it has been detected in space by astronomers using the European Southern Observatory-operated Atacama Pathfinder Experiment (APEX) telescope in Chile.

An international team of astronomers made the discovery with APEX, situated on the 16,400-foot-high (5,000 meters) Chajnantor plateau in the Chilean Andes. They observed a region in our galaxy close to the star Rho Ophiuchi, about 400 light-years away. The region contains cold (around -420° Fahrenheit [-250° Celsius]), dense clouds of cosmic gas and dust in which new stars are being born. The clouds are mostly made of hydrogen, but contain traces of other chemicals, and are prime targets for astronomers hunting for molecules in space. Telescopes such as APEX, which make observations of light at millimeter- and submillimeter-wavelengths, are ideal for detecting the signals from these molecules.

Now, the team has found the characteristic signature of light emitted by hydrogen peroxide, coming from part of the Rho Ophiuchi clouds.

“We were really excited to discover the signatures of hydrogen peroxide with APEX. We knew from laboratory experiments which wavelengths to look for, but the amount of hydrogen peroxide in the cloud is just one molecule for every 10 billion hydrogen molecules, so the detection required very careful observations,” said Per Bergman from Onsala Space Observatory in Sweden.

Hydrogen peroxide (H2O2) is a key molecule for both astronomers and chemists. Its formation is closely linked to two other familiar molecules, oxygen and water, which are critical for life. Because much of the water on our planet is thought to have originally formed in space, scientists are keen to understand how it is created.

Hydrogen peroxide is thought to form in space on the surfaces of cosmic dust grains — fine particles similar to sand and soot — when hydrogen (H) is added to oxygen molecules (O2). A further reaction of hydrogen peroxide with more hydrogen is one way to produce water (H2O). This new detection of hydrogen peroxide will therefore help astronomers better understand the formation of water in the universe.

“We don’t understand yet how some of the most important molecules here on Earth are made in space,” said Berengere Parise from the Max Planck Institute for Radio Astronomy in Germany. “But our discovery of hydrogen peroxide with APEX seems to be showing us that cosmic dust is the missing ingredient in the process.”

To work out just how the origins of these important molecules are intertwined will need more observations of Rho Ophiuchi and other star-forming clouds with future telescopes such as the Atacama Large Millimeter/submillimeter Array — and help from chemists in laboratories.